Methods of and systems for encoding and decoding a beam of light utilizing nonlinear organic signal processors

ABSTRACT

An audio optical processor unit employing a nonlinear organic optical element which may be in the form of a nonlinear polymer, a nonlinear organic material or a mixture of liquid crystal materials or polymers. The nonlinear organic optical element is interfaced by a piezo-electric crystal which encodes a laser beam passing through the optical element by inducing changes in the index of refraction or the changes in voltage potential across the polymer or non-linear organic material. The resulting encoded output is detected in a conventional manner by a photodetector array.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The instant invention relates to audio optical signal processors anddecoders, and more particularly, the instant invention relates to suchprocessors and decoders which rely on electro-optic, piezo-electriccrystal technology in combination with nonlinear crystals and the likeutilized in signal-information processing techniques and audio andspeech processing techniques.

2. Prior Art

Audio and digital decoders and translators; encryption devices, and realtime audio translation and printed output and graphic devices generallyrely on nonlinear inorganic crystals such as lithium niobate to modulateand demodulate optical signals. The chemical and physical differencesbetween nonlinear inorganic crystals and nonlinear organic crystals arelegion. While there are literally millions of noncentrosymmetric organiccompounds which have nonlinear optical properties, there are only a fewinorganic compounds having such properties. To date, inorganic crystalshave been relied on in most electro-optical applications due to therelative simplicity of the crystalline configuration thereof wherein thecrystals rely on ionic attraction to form molecules from associatedatoms. Organic molecules, however, are held together by covalent forcesand share valence electrons among atomic centers thereof. This resultsin compounds such as polymers which are easier to fabricate, shape andengineer into particular geometric designs than are inorganic compoundswhich are difficult and expensive to fabricate and synthesize since theyare generally created by growing appropriate crystalline structures.

To date, reliance on inorganic crystals for electro-optical applicationslimits new development and flexibility of optical signal processingtechnology.

SUMMARY OF THE INVENTION

A method of encoding a beam of light comprises the steps of passing thelight through an optical body of nonlinear organic material whilecontrolling the molecular orientation of the material to produce anencoded or decoded optical output.

The nonlinear organic material may be one of a number of polymers,organic dyes, mixtures of liquid crystal materials or other organicmaterials.

In accordance with a preferred embodiment, the molecular orientation ofthe material is controlled by a piezo-electric crystal which interfacesdirectly with the nonlinear organic element or body.

The instant invention further comprises an optical system for encoding amonochromatic beam of light wherein the system includes an optical bodyof nonlinear organic material and a device for controlling the molecularorientation of the material to encode the beam of light. The nonlinearorganic material may be a polymer selected from a wide range ofpolymers, other organic materials or a mixture of liquid crystalmaterials.

BRIEF DESCRIPTION OF THE DRAWINGS

Various other objects, features and attendant advantages of the presentinvention will be more fully appreciated as the same becomes betterunderstood when considered in conjunction with the accompanyingdrawings, in which like reference characters designate the same orsimilar parts throughout the several views, and wherein:

FIG. 1 is a diagrammatical view illustrating a system utilizing anonlinear element in an audio-optical signal processor and decoder;

FIG. 2 is a diagrammatical view illustrating a crystal control interfaceand nonlinear processing element coupled to produce information outputsand encodings;

FIG. 3 is a diagrammatical view illustrating a nonlinear processingelement linked to a series of parallel processors;

FIG. 4 is a diagrammatical view illustrating an optical signal decoderand processor utilizing a liquid crystal display as an input controlinterface;

FIG. 5 is a diagrammatical view illustrating an optical signal decoderand processor using a nonlinear organic polymer as an input controlinterface;

FIG. 6 is a schematic view showing the basic concept of an opticalacoustic processor encoding information on a reference laser beam;

FIG. 7 is a schematic view showing an audio optical processor producingcontrolled diffraction of a reference beam through changes in the indexof refraction in a nonlinear organic polymer or material;

FIG. 8 is a schematic view showing an audio optical processor usingaudio inputs to induce changes in voltage potential across a nonlinearpolymer or material; and

FIG. 9 is a schematic view showing an audio optical processor utilizingaudio inputs to control diffracted outputs.

DETAILED DESCRIPTION

Referring now to FIG. 1, there is shown an overall system diagram for anoptical signal processor and decoder, designated generally by thenumeral 10, and configured in accordance with the principles of theinstant invention. The controller 10 utilizes a nonlinear processingelement 11 which is controlled by a piezo-electrical crystal 12 thatabuts the nonlinear processing element along an interface 13 to providea crystal interface which relies on the piezo-electric properties ofquartz or similar materials. The nonlinear processing element 11 iscontrolled by changes in the piezo-electric interface 13 of the crystal12 with the nonlinear element.

The quartz crystal/piezo-electrical effect utilizes its resonantfrequency properties to control the molecular orientation within thenonlinear crystal 11 so as to in effect tune the molecular orientationsthereof, either through piezo-electric potential changes or crystalresonant frequencies. Monochromatic light 14 from a laser or LED 16 ismodulated by the nonlinear element 11 prior to detection by aphotodetector ray 17.

Considering the system generally, the piezo-electric crystal 12 and thelaser or LED 16 are controlled by the circuit comprised of informationalinputs in the form of a digital interface or keyboard 20 and anaudio/speech interface or microphone 21 which are connected by asignal/databus 22 to electronic interface circuitry 23. The electronicinterface circuitry 23 is applied through a signal control andconditioner circuit 24 to the piezo-electric crystal 12 to tune themolecular orientations within the nonlinear element 11 via an interfacecoupling 26. The laser or LED 16 is connected via line 27 to the bus 22so as to be controlled by the digital interface or keyboard 20.

The photodetector array 17, which may include a series of photodiodes28, is connected by an output 29 to a signal processor 31 which ispreferably in the form of a digital signal processor chip. The output ofthe signal processor 31 is applied to the output device 32 which may,for example, be a printer or display. Microprocessor control 33 controlsthe operation of the system via outputs to the signal/databus 22 and theelectronic interface circuits 23 and has a facility 34 for external ormanual inputs or commands. With the exception of the nonlinear opticalelement 11 and the associated piezo-electric interface 13 activated bythe piezo-electric crystal 12, the aforedescribed system is comprised ofknown components.

Referring now to FIG. 2, the crystal control interface 13 and nonlinearprocessing element 11 of nonlinear optical materials is shown connectedoptically to the photodetector array 17 to produce information outputsand encodings for enhancing speed and signal/information processing fornumerous applications such as speech synthesis and translation,encryption and decoding, and direct output interfacing in real time tovarious computational printers' graphic devices and audio devices.

The following nonlinear optical materials are exemplary of the materialsutilized in the nonlinear optical element 11 of FIG. 2:

1. Cyanine dyes;

2. 2-methyl-4-nitroaniline (MNA);

3. Indanthrones;

4. Stilbenes;

5. Pyridine N-oxides;

6.2-(p-dimethylaminophenyl)-6-(p-nitrophenyl)-benzo(1,2-d:4,5-d')bis-thiazole(DNBT);

7. 2-(4-(dimethyl-amino)phenyl)-5-nitrobenzoxazole.

In FIG. 3, there is shown an optical crystal processor for processingdigital signal inputs to produce digital outputs 36 from monochromaticlight 37 which is processed by the nonlinear processing element 11 whichis controlled by the piezo-electric crystal 12 through the interface 13.The piezo-electric crystal 12 transmits a digital, keyboard inputthrough the nonlinear processing element 11 to modulate themonochromatic light 37 so as to produce the encoded light 36. Thephotodetector array 17 responds to a digital word format, such as a32-bit word format, and provides a 32-bit digital output through eithersignal processor 31 or to a series of parallel processors 40 to performparallel processing functions.

Referring now to FIG. 4, an incident monochromatic light beam 41 from alaser is applied through a nonlinear processing element wherein thenonlinear processing element is in the form of a liquid crystal array42. The liquid crystal array 42 may be controlled via an input controlinterface 43 supplied by a connection with a piezo-electric crystal, anda source of alternating current or an applied resonant frequency. Theinput control interface 43 changes the orientation of the liquidcrystals in the array 42 to allow or encode light at differentpolarizations to be transmitted to the photodetection array 44, therebyreceiving and sampling for analysis the incoming beam 41 of transmittedlaser light. With this arrangement, different packets of digitalinformation represented by lines 47, 48 and 49 are diverted to differentlocations represented by areas 51-57 on the photodetector array 44. Asignal processor 58 analyzes the location of the detector areas 51-57which have received the different information packets 47-49 and a signalprocessing operation correlates the information with an associateddatabase or sequence, thus decoding the information received.

Generally liquid crystal materials are mixtures of numerous materials.Exemplary of such mixtures and materials which may be used to comprisethe liquid crystal array 42 are disclosed in U.S. Pat. Nos. 4,621,901;4,662,283; 4,670,182 and U.S. Pat. No. 4,707,296, all incorporatedherein by reference.

Referring now to FIG. 5, the various elements are the same as FIG. 4;however, the nonlinear element is in the form of a nonlinear organicpolymer 60 which has variations in refraction indices induced by phononinteractions. These variations control the incident monochromatic light41 to produce the encoded or decoded light packets 47, 48 and 49, whichare applied to the various areas 51-57 of the photodetector array 44.

Examples of organic polymer materials which are fabricated intononlinear processing elements 60 according to the invention are:

1. 4,4'-oxynitrobiphenyl methacrylates;

2. N-oxypyridyl cyanophenoxy methacrylates;

3. Poly(p-phenylenebenzo[1,2-d:4,5-d']bisthiazole (PBT);

4. Emeraldine salt forms of polyaniline;

5. Polyacetylenes;

6. Dye substituted polyethers.

The light sources 16 and 41 of FIGS. 1-5 are preferably either standarddye lasers or neodymium YAG lasers. Preferably, the interface 13 of thenonlinear optical elements 11, 42 and 60 with the piezo-electriccrystals 12 and 43 have a film thickness in the range of about 1 to 5microns and a channel length in the range of about 10 to 50 microns andpreferably about 25 microns. The photodetectors or photoreceptors ofFIGS. 1-5 are of conventional photosensitive materials, such asgermanium, indium, gallium arsenide, lead selenide, lead sulfide andmercury cadmium telluride.

Referring now to FIGS. 6, 7, 8 and 9 where four configurations of theaudio optical processor element 11 (FIG. 1) is shown in greater detailin combination with the piezo-electric crystal 13 and photodetectorarray 17. The basic design shown in FIG. 6 of the audio processor unitinterfaces the piezo-electric crystal 12 with the nonlinear polymer ormaterial 11 across an interface 13. The nonlinear polymer or material 11is contained in a cell 70 comprised of a conductive NESA glassenclosure. The electrical input over line 71 through the connector 72induces proportional stresses in the piezo-electric crystal 12 which isdirectly interfaced with the nonlinear organic polymer or material 11,thus inducing proportional changes in the index of refraction of thematerial. These proportional changes control or direct the outputdiffraction 73 of the reference laser light 74 (14 in FIG. 1). Theoutput is then detected by the photodetector array 17 and transmitted tothe signal processor 12 of the system 10 (see FIG. 1).

Referring now to FIG. 7, the audio optical process produces a designatedor controlled diffraction of the reference beam 74 through controlled orinduced changes in the index of refraction in the nonlinear organicpolymer or material 11 and thus the diffracted output 75 is offset by anangle .o slashed. with respect to the input beam 74 of laser light. Thephotodetector array 17 is oriented so that the diffracted output beam 75strikes the photodetectors orthogonally.

Referring now to FIG. 8, a signal 78 from an audio transducer outputsuch as a microphone is applied to the piezo-electric crystal 12 so asto induce changes in the nonlinear polymer or material 11 which areproportional to changes in the voltage potential across the polymer.This results in an encoded beam output 80 which impinges on thephotodetector array 17.

Referring now to FIG. 9, an arrangement similar to FIG. 8 is shownwherein audio inputs 78 are utilized to control or produce diffractedoutputs 81 wherein the outputs 81 are at an angle .o slashed. withrespect to the inputs 74. The photodetector array 17 is oriented so thatthe diffracted output 81 impinges orthogonally with respect to the planeof the photodetector array.

From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention, and withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions.

What is claimed is:
 1. A method of encoding a beam of light comprisingthe steps of passing coherent, monochromatic light through an opticalbody of nonlinear organic material while controlling the diffraction ofsaid light so as to produce an encoded or decoded optical output.
 2. Themethod of claim 1, wherein the nonlinear organic material is a materialselected from the group consisting of:Cyanine dyes;2-methyl-4-nitroaniline (MNA); Indanchrones; Stilbenes; PyridineN-oxides;2-(p-dimethylaminophenyl)-6-(p-nitrophenyl)-benzo(1,2-d:4,5-d')bis-thiazole(DNBT); 2-(4-(dimethyl-amino)phenyl)-5-nitrobenzoxazole.
 3. The methodof claim 1, wherein the diffraction of said light is caused by periodicchanges in the refractive index of said nonlinear organic material whichresult from the transmission of acoustic waves generated by apiezo-electric crystal.
 4. A method of encoding a beam of lightcomprising the steps of passing coherent, monochromatic light through anoptical body of nonlinear organic material while controlling thediffraction of said light so as to produce an encoded or decoded opticaloutput, wherein the diffraction of said light is caused by periodicchanges in the refractive index of said nonlinear organic material whichresult from the transmission of acoustic waves generated by apiezo-electric crystal, and the piezo-electric crystal interfacesdirectly with the nonlinear body.
 5. The method of claim 4, wherein thebeam of light is modulated by an audio input applied through thenonlinear organic material via the piezo-electric crystal.
 6. Theprocess of claim 5, wherein the piezo-electric crystal is controlled bya digital input control signal.